An improved filter trap for use in a cable system is disclosed in U.S. Pat. No. 5,278,525 to Palinkas, the disclosure of which is incorporated herein by reference. The Palinkas device is illustrated in FIG. 1 and is generally referenced 10. The device includes a pair of housings 12 and 13 each of which contains filter components for removing or attenuating signals at selected frequencies so that the selected signals will not reach a subscribers location in a usable form. The housings are coaxially aligned along a common center axis 15 with the adjacent end walls 17 and 18 of the housings being mounted in close proximity. To one another an electrical isolation shield 20 is mounted between the housings to maintain separation between the two and to prevent flux generated by the filters from crossing over between the housings. The isolation shield is a disc shaped member having opposed end faces that are perpendicularly aligned with reference to the common axis 15. A pair of off axis keys 21—21 are carried upon each end face of the shield which mate with complementary keyways 22—22 formed in the adjacent end walls of the two housings. The two filter housings and the isolation shield are, in assembly, contained within a tubular sleeve 25 and suitable gaskets 26 and 27 are provided at the two ends of the sleeve to prevent moisture and other contaminants from passing between the sleeve and the housings.
A cut out 29 is provided in the shield which permits an off axis electrical lead 30 to pass between the housings. Housing 12 is equipped with an end cap 31 having a female threaded connector 33 containing a terminal pin 35 that enables the housing to be coupled to a coaxial cable. The second housing 13 contains an end cap 36 having a male threaded connector 37 which contains a connector terminal (not shown) for coupling the housing to the second coaxial cable.
Theft of service has long been a problem in the cable industry. Most distribution boxes or taps servicing most cable systems are readily accessible to the general public. All the signals provided by the network are carried to the tap on the providers cable. However, only the signals that are paid for by a subscriber are tapped onto the subscribers cable, the remaining signal being blocked or attenuated by filter traps that are located in the distribution box.
If a subscriber wishes to gain illegal access to the blocked or attenuated signals, he or she can simply remove the blocking or attenuating filters and connect the subscribers cable directly to the tap input. This type of tampering with the tap connection is, however, easily detected by a visual inspection of the distribution box.
It has been found, however, that the prior art filter assembly described in the above noted Palinkas patent can be circumvented in manner that is not easily detected by a visual inspection. This is achieved by removing the filter housing from the tap and drilling or otherwise creating a passage running along the commonly shaped axis between the two end connectors of the assembly. The center connectors of a coaxial cable can then be passed through the passage between the connectors to bypass the filters. The assembly, so altered, is then reinstalled in the distribution box in its original location. A service person inspecting the system can see the filter assembly is in place and without further inspection, it is assumed it is working properly to block or attenuate signal at the tuned frequencies.